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A230806 The smallest of 4 consecutive palindromic numbers that are all primes. 2
1878781, 11782828711, 13828882831, 33694849633, 36331813363, 76093839067, 93121812139, 1018278728101, 1101228221011, 1200528250021, 1237788877321, 1296978796921, 1318608068131, 1449108019441, 1477968697741, 1608678768061, 1713708073171, 1792308032971 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
There cannot be 5 consecutive palindromic numbers that are all primes. The central digit of all numbers in the sequence will be 8.
LINKS
EXAMPLE
1878781 is in the sequence because 1878781, 1879781, 1880881 and 1881881 are consecutive palindromic numbers that are all primes.
MATHEMATICA
a = {}; m = 0; Do[z = n*10^(IntegerLength[n] - 1) + FromDigits@Rest@Reverse@IntegerDigits[n]; If[PrimeQ[z], m = m + 1; If[m == 1, z1 = z]; If[m == 4, AppendTo[a, z1]], m = 0], {n, 1, 1000000000}]
CROSSREFS
Sequence in context: A251008 A064820 A032595 * A032596 A032597 A203794
KEYWORD
nonn,base
AUTHOR
Shyam Sunder Gupta, Oct 30 2013
STATUS
approved

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Last modified July 21 18:17 EDT 2024. Contains 374475 sequences. (Running on oeis4.)